ABSTRACT Depressive and anxiety disorders affect 20-30% of school age youth, contributing to poor developmental and academic outcomes. Psychosocial evidence-based practices such as cognitive behavioral therapy (CBT), can improve outcomes in these disorders, but numerous barriers limit access. Students access mental health services at schools more than anywhere else, but school professionals (SPs, e.g., counselors, social workers) are generally not trained to deliver CBT. Efficient and successful implementation of CBT in schools requires scientific study of implementation strategies designed to optimize uptake, addressing student, SP, and community barriers. Replicating Effective Programs (REP), Coaching, and Facilitation are three previously established implementation strategies, but vary in intensity and theoretical foundation. REP combines customized intervention packaging, didactic training, and technical support to improve provider knowledge. Coaching extends didactic training via ongoing, live supervision to improve provider competence and acceptance. Facilitation mentors providers in strategic thinking to promote self-efficacy in championing the use of effective practices and securing administrator support. Coaching and Facilitation can be expensive and may be unnecessary for early adopters. An adaptive implementation intervention can be used to provide the more intensive implementation strategies only to those who need them. The primary aim of this study is to compare the effectiveness of two adaptive implementation interventions on the frequency of CBT delivered to students by SPs (primary outcome) and on student depressive and anxiety symptoms (secondary outcomes). Schools will first be randomized to receive REP or REP + Coaching. Schools in need of additional assistance will subsequently be randomized to continue with REP or REP+Coaching or to receive added Facilitation. Secondary aims include determining moderators of implementation effects (e.g., social determinants, leadership support), determining the cost of early introduction of Coaching and/or augmentation with Facilitation, and identifying the mechanisms by which Coaching and Facilitation improve CBT use among SPs and impact student outcomes. This five-year implementation trial will apply a novel sequential multiple assignment randomized trial (SMART) design across a network of schools in all 83 counties in Michigan, involving over 100 schools, 200 SPs, and over 2000 students. Web-based tools will facilitate data collection from SPs and students. This will be the first study to test implementation of a transdiagnostic EBP for school-age youth, at a statewide level, delivered by school staff ? taking the treatment to populations with limited access. The proposal addresses two national health priorities: 1) reducing mental health care and provider capacity gaps affecting youth, and 2) enhancing the knowledge base of implementation science in community settings; and NIMH strategic goal 4: strengthening public health impact of research through community partnerships (4.2) and implementation strategies (4.3).